Hisonotus charrua Almirón, Azpelicueta, Casciotta & Litz, 2006

Carvalho, Tiago Pinto & Reis, Roberto E., 2011, Taxonomic review of Hisonotus Eigenmann & Eigenmann (Siluriformes: Loricariidae: Hypoptopomatinae) from the laguna dos Patos system, southern Brazil, Neotropical Ichthyology 9 (1), pp. 1-48 : 21-22

Hisonotus charrua Almirón, Azpelicueta, Casciotta & Litz, 2006

Fig. 20c

Hisonotus charrua Almirón et al., 2006: 88 [original description, type locality: Uruguay, Departamento Tacuarembó, río Uruguay basin, Canãda de Los Penã]. -Reis & Carvalho, 2007: 83 [listed]. Reis & Carvalho, 2009: 35 [included in key].

Hisonotus sp. 2 . Cramer et al., 2007: 54 [included in molecular phylogeny of Loricariidae ].

Diagnosis. Hisonotus charrua differs from its congeners, except from H. armatus , H. leucophrys , H. leucofrenatus , H. laevior , H. notopagos , and H. taimensis by the color pattern of the caudal fin, which has a conspicuous hyaline transversal band composed by clear spots (a second posterior band in larger individuals) in a dark background, vs. hyaline areas not forming a clearly defined transversal bands in the middle portion of caudal fin. Hisonotus charrua is distinguished from H. armatus , H. leucophrys , and H. leucofrenatus by having a narrow naked band without odontodes on the anterior margin of snout, vs. snout completely covered by odontodes; and from H. laevior , H. notopagos , and H. taimensis by the number of lateral plates 23-25 ( Table 2), vs. 25-28 plates; by the number of predorsal plates, 3, vs. 3-4 (modally 4) predorsal plates; and by the number of vertebrae 28-29, vs. 30-32 vertebrae.

Description. This species was recently described by Almirón et al. (2006) and will not be redescribed here.

Distribution and habitat. Hisonotus charrua is widely distributed in the middle and lower portions of the rio Uruguay basin from the northern rio Ijuí drainage in the Rio Grande do Sul State, Brazil, to the southern río Negro drainage in Uruguay. Besides the limits of the rio Uruguay basin, this species is known from the coastal streams of Uruguay, and from the headwaters of Jaguarão and São Gonçalo drainages in the laguna dos Patos system ( Fig. 22). The species is sympatric with H. ringueleti Aquino, Miquelarena & Schaefer along its distribution in the middle rio Uruguay basin (Carvalho & Reis, 2009). Hisonotus charrua is collected together with H. nigricauda in several streams tributaries to rio Ibicuí and río Negro drainages. This species inhabits a variety of habitats, usually small to medium size creeks with loose stones, and gravel bottom, with median to rapid-flowing water. Collected associated to marginal vegetation composed by grasses or Echinodorus uruguayensis ( Almirón et al., 2006)

Remarks. No morphological differences were found between populations of Hisonotus charrua from rio Uruguay basin and the headwaters of rio Jaguarão and rio São Gonçalo drainages in the laguna dos Patos system ( Table 5). Cramer et al. (2007) in a molecular phylogeny of Hypoptopomatinae + Neoplecostominae, using a mitochondrial gene (cytochrome c oxidase I), included a sample from the laguna dos Patos system population of H. charrua ( Hisonotus sp. 2 - MCP 25139). According to these authors, the H. charrua haplotype from the laguna dos Patos system is sister to H. laevior , while the H. charrua haplotype from rio Uruguay has a more basal position in a clade composed also of H. taimensis and H. armatus . However, there is low resolution in this clade and it seems necessary the inclusion of more samples/genes to unambiguously determine the phyletic status of the H. charrua morphospecies.

Material examined. From laguna dos Patos system: Rio São Gonçalo drainage: MCP 25139, 15 + 2 c&s, 32.4-46.4 mm SL, Brazil, Pinheiro Machado, arroio dos Pires on bridge of railroad at Passo dos Pires, 31º38’S 53º27’W . Rio Jaguarão drainage : MCP 44500, 10 , 16.9-45.4 mm SL, Brazil, Pedras Altas, creek tributary to arroio Jaguarão at Fazenda Sao Francisco II, 31º53’09”S 53º36’45”W . From rio Uruguay basin: Río Negro drainage: ZVC- P 5639, holotype, 49.2 mm SL, Uruguay, Tacuarembó, Cañada de Los Peña, 31º39’05”S 56º12’19”W . AI 165, paratypes, 5, 37.1- 48.7 mm SL, collected with the holotype . MCP 9648 , 1 , 34.2 mm SL, Brazil, Bagé, rio Negro on bridge of highway BR-293 between Bagé and Aceguá, 31º21’S 54º03’W . MCP 16177, 3 , 27.1-36.1 mm SL, Brazil, Bagé, rio Piraizinho on road from Bagé to Dom Pedrito , 31º17’S 54º09’W . MCP 40256, 4 + 1 c&s, 32.8-50.3 mm SL, same locality of holotype . UFRGS 9242 , 15 , 26.6-38.3 mm SL, Uruguay, Durazno, arroyo Maestre de Campo on road to Polanco de Yí, tributary of río Yí , 33º24’55”S 56º12’06”W . UFRGS 7184 , 9 + 2 c&s, 18.0- 46.2 mm SL, Uruguay, Rivera, lateral pools and arroyo Corrales on ruta 27, tributary of río Tacuarembó, 31º23’26”S 55º15’14”W . UFRGS 7185 , 12 , 15.9-39.8 mm SL, Uruguay, Rivera, arroyo Batovi at km 24 of ruta 27, tributary of río Tacuarembó drainage . UFRGS 7186 , 3 , 15.8-20.6 mm SL, Uruguay, Tacuarembó, arroyo Batovi on km 365 of ruta 5, about 20 km from Tacuarembó, 31º43’S 55º46’W . UFRGS 7187 , 3 , 16.1- 28.3 mm SL, Uruguay, Rivera, arroyo Cunãpiru on km 12 of ruta 27, río Tacuarembó drainage, 31º02’21”S 55º29’31”W . Other drainages of rio Uruguay: MACN 7593 , 1 , 40.5 mm SL, Argentina, Entre Ríos, Parque Nacional El Palmar . UFRGS 7977 , 2 , 32.7-38.5 mm SL, Artigas, Uruguay, arroyo Guaviyú on ruta 3, 30º38’00”S 57º41’16”W . UFRGS 9195 , 8 , 25.1-40.9 mm SL, Uruguay, Artigas, arroyo Mandiyú on ruta 3, 30º51’55”S 57º39’57”W . AI 176, paratype, 1, 35.9 mm SL, Uruguay, Salto, arroyo Aspinillar at Constitución. Uruguay coastal drainages : MAPA 1969 , 15 , 14.7-47.2 mm SL, Uruguay, Maldonado, San Carlos, arroyo Maldonado . MCP 40257, 3 , 37.3-40.3 mm SL, Uruguay, Canelones, arroyo Tropa Vieja, 34º44’59”S 55º50’46”W . MCP 40255, 38.8 mm SL, Uruguay, Canelones, arroyo Sauce on km 38 of ruta 7, 34º38’48”S 55º58’27”W . Rio Quaraí drainage: AI 186, paratype, 1, 40.5 mm SL, Uruguay, Artigas, arroyo Catalán Grande, 30º50’40”S 56º12’19”W . MCP 11351, 3 , 12.8-18.4 mm SL, Brazil, Quaraí , small creek affluent of arroio Garupá, 30º09’S 56º13’W . MCP 35303, 3 , 33.8-41.5 mm SL, Brazil, Quaraí, arroio Garupá on road from Quaraí to Harmonia, about 33 km northeast of Quaraí , 30º09’45”S 56º14’08”W . MCP 40904, 23 + 4 c&s, 17.6-45.6 mm SL, Brazil, Quaraí , arroio Quaraí-Mirim on road between Uruguaiana and Quaraí, 30º18’S 56º19’W . UFRGS 7926 , 1 , 21.1 mm SL, Uruguay, Artigas, arroyo Yucutujá on ruta 3. Rio Ibicuí drainage : MCP 9630 , 2 , 23.4-33.4 mm SL, Brazil, Dom Pedrito, rio Santa Maria at km 246 of highway BR-293, between Dom Pedrito and Santana do Livramento, 30º59’S 54º42’W . MCP 23090, 1 , 44.4 mm SL, Brazil, São Francisco de Assis, arroio Sanga Funda about 15 km southeast from São Francisco de Assis , 29º39’02”S 55º00’06”W . MCP 27539, 4 + 2 c&s, 28.8-46.6 mm SL, Brazil, Jaguari, arroio do Tigre on highway BR-453/ Ijucapirama, about 2,5 km northeast from BR-453, 29º28’18”S 54º40’19”W . MCP 27567, 1 , 28.6 mm SL, Brazil, Jaguari, creek affluent of rio Tunas on highway BR-453/ Ijucapirama, tributary to rio Jaguari , 29º26’27”S 54º35’35”W . MCP 27604, 7 , 15.2-35.3 mm SL, Brazil, Jaguari, arroio Capivari on highway BR-453/ Jari, tributary to rio Jaguari , 29º21’10”S 54º28’32”W . MCP 27611, 15 , 16.5-40.7 mm SL, Brazil, São Francisco de Assis, arroio Caraí- Passo on road from São Francisco de Assis to Manuel Viana, 29º31’03”S 55º10’49”W . MCP 27625, 3 , 29.8 -37.0 mm SL, Brazil, Tupanciretã, rio Santana near Jari, tributary to rio Jaguari , 29º14’33”S 54º16’47”W . MCP 41631, 5 , 34.4-39.74 mm SL, Brazil, São Francisco de Assis, rio Inhacunda at São Francisco de Assis going to Manuel Viana, 29º32’51”S 55º08’11”W . MCP 41634, 6 , 19.1-37.2 mm SL, Brazil, São Francisco de Assis, creek affluent to rio Inhacunda at São Francisco de Assis about 300 m from potery . UFRGS 2576 , 1 , 34.5 mm SL, Brazil, Santa Maria , arroio Taquara at km 10 on highway RS-453 between Santa Maria and Santiago. UFRGS 8332 , 3 , 36.8-39.7 mm SL, Brazil, Bagé, rio Santa Maria on highway BR-293 between Bagé and Dom Pedrito, 31º08’S 54º22’W . UFRGS 8333 , 1 , 40.4 mm SL, Brazil, Bagé, arroio Santa Maria Chico affluent of rio Santa Maria on highway BR-293, 31º04’S 54º29’W . Rio Ijuí drainage : MCP 9616 , 1 , 32.5 mm SL, Brazil, Panambi, riacho Raiz Mana at Condor on road from Palmeira das Missões to Panambi, 28º13’S 53º29’W . MCP 16751, 1 , 34.5 mm SL, Brazil, Jóia, creek affluent of rio Ijuizinho near Jóia, on road from Eugênio de Castro to Jóia, 28º39’S 54º07’W . MCP 34968, 2 c&s, 19.3-34.9 mm SL, Brazil, Roque Gonzales, arroio Portão, 28º06’21”S 54º58’33”W . MCP 37232, 2 + 2 c&s, 36.1-38.4 mm SL, Brazil, São Pedro do Butiá , arroio Albino, 28º08’10”S 54º55’28”W . MCP 37270, 4 , 23.1-33.6 mm SL, Brazil, Dezesseis de Novembro , lageado Araçá, 28º12’23”S 54º56’58”W . UFRGS 4329 , 3 , 37.8-45.6 mm SL, Brazil, Panambi, rio Caxambu , at km 275 of highway BR-285, 28º19’S 53º39’W .